U.S. patent application number 16/628678 was filed with the patent office on 2020-07-09 for drive device for a vehicle flap.
The applicant listed for this patent is Edscha Engineering GmbH. Invention is credited to Jochen BALS, Andre WIRTH.
Application Number | 20200217118 16/628678 |
Document ID | / |
Family ID | 62975814 |
Filed Date | 2020-07-09 |
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United States Patent
Application |
20200217118 |
Kind Code |
A1 |
WIRTH; Andre ; et
al. |
July 9, 2020 |
DRIVE DEVICE FOR A VEHICLE FLAP
Abstract
A drive device for a pivoting vehicle flap, includes a first
housing part (3), a second housing part (4), wherein the first
housing part (3) and the second housing part (4) are designed to be
movable toward each other in the direction of the axial extension
(x) of the drive device (1), a spindle rod (12) rotatably arranged
on one of the first housing part (3) and the second housing part
(4) and a spindle nut (13) arranged in a rotatably fixed manner on
the other of the first housing part (3) and the second housing part
(4), a braking device (19), comprising a first brake element, which
is connected to the spindle rod (12) in a rotatably fixed manner, a
second brake element, which is connected to one of the first
housing part (3) and the second housing part (4) in a rotatably
fixed manner, wherein the first brake element can interact with the
second brake element in order to generate a brake force, and a
magnet arrangement for generating a magnetic field. The drive
device (1) is for a pivoting vehicle flap, to provide automatic
pivoting and a flexible holding force for the vehicle flap, such
that at least one of the first brake element and the second brake
element can be displaced in the axial direction (x) of the spindle
rod (12) by the magnetic field.
Inventors: |
WIRTH; Andre; (Remscheid,
DE) ; BALS; Jochen; (Dortmund, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Edscha Engineering GmbH |
Remscheid |
|
DE |
|
|
Family ID: |
62975814 |
Appl. No.: |
16/628678 |
Filed: |
July 6, 2018 |
PCT Filed: |
July 6, 2018 |
PCT NO: |
PCT/DE2018/100624 |
371 Date: |
January 5, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E05Y 2201/70 20130101;
F16H 25/2454 20130101; E05Y 2201/462 20130101; E05Y 2201/246
20130101; F16H 2025/2075 20130101; E05Y 2900/546 20130101; E05Y
2201/702 20130101; E05F 15/622 20150115; E05F 3/00 20130101; E05Y
2900/531 20130101; E05Y 2201/25 20130101; E05Y 2201/21
20130101 |
International
Class: |
E05F 3/00 20060101
E05F003/00; F16H 25/24 20060101 F16H025/24; E05F 15/622 20060101
E05F015/622 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 6, 2017 |
DE |
10 2017 115 183.4 |
Claims
1-10. (canceled)
11. A drive device for a pivotable vehicle flap, comprising a first
housing part, a second housing part, wherein the first housing part
and the second housing part are configured to be movable relative
to each other in a direction of an axial extension of the drive
device, a spindle rod rotatably arranged on one of the first
housing part and the second housing part, a spindle nut
non-rotatably arranged on the other of the first housing part and
the second housing part, a brake device comprising a first brake
element, the brake device further comprising a second brake element
non-rotatably connected to one of the first housing part and the
second housing part, wherein the first brake element is
interactable with the second brake element to generate a braking
force, and a magnet arrangement for generating a magnetic field,
wherein the first brake element is non-rotatably connected to the
spindle rod, and wherein the first brake element is displaceable in
an axial direction of the spindle rod by the magnetic field.
12. The drive device according to claim 11, wherein the first
housing part and the second housing part are components of a
housing of the drive device, wherein the first housing part and the
second housing part are arranged concentrically with respect to
each other.
13. The drive device according to claim 11, wherein the magnet
arrangement comprises an electromagnet.
14. The drive device according to claim 11, wherein the magnet
arrangement comprises a permanent magnet.
15. The drive device according to claim 14, wherein the permanent
magnet magnetically attracts the first brake element toward the
second brake element.
16. The drive device according to claim 11, wherein the one of the
first brake element and the second brake element can be displaced
in the axial direction so far toward the other of the first brake
element and the second brake element that the first brake element
and the second brake element can touch each other.
17. The drive device according to claim 11, wherein the first brake
element has a first friction surface and the second brake element
has a second friction surface.
18. The drive device according to claim 17, wherein the first
friction surface and the second friction surface face each other
and are aligned perpendicularly to the axial direction of the
spindle rod.
19. The drive device according to claim 11, wherein the magnet
arrangement is arranged on the second brake element.
20. A drive device for a pivotable vehicle flap, comprising a first
housing part, a second housing part, wherein the first housing part
and the second housing part are configured to be movable relative
to each other in a direction of an axial extension of the drive
device, a spindle rod rotatably arranged on one of the first
housing part and the second housing part, a spindle nut
non-rotatably arranged on the other of the first housing part and
the second housing part, a brake device comprising a first brake
element and a second brake element, wherein one of the first brake
element and the second brake element is displaceable in an axial
direction of the drive device so far toward the other of the first
brake element and the second brake element that the first brake
element and the second brake element can touch each other, and a
magnet arrangement for generating a magnetic field, wherein the
first brake element is displaceable in an axial direction of the
spindle rod by the magnetic field.
21. The drive device according to claim 20, wherein the magnet
arrangement comprises an electromagnet.
22. The drive device according to claim 20, wherein the first brake
element has a first friction surface and the second brake element
has a second friction surface.
23. The drive device according to claim 22, wherein the first
friction surface and the second friction surface are facing each
other and are aligned substantially perpendicularly to the axial
direction of the spindle rod.
24. A drive device for a pivotable vehicle flap, comprising a first
housing part, a second housing part, wherein the first housing part
and the second housing part are configured to be movable relative
to each other in a direction of an axial extension of the drive
device, a spindle rod rotatably arranged on one of the first
housing part and the second housing part, a spindle nut
non-rotatably arranged on the other of the first housing part and
the second housing part, a brake device comprising a first brake
element non-rotatably connected to the spindle rod, a second brake
element non-rotatably connected to one of the first housing part
and the second housing part, wherein the first brake element is
interactable with the second brake element to generate a braking
force, and a magnet arrangement for generating a magnetic field,
wherein the magnet arrangement comprises an electromagnet and a
permanent magnet, and wherein at least one of the first brake
element and the second brake element is displaceable in an axial
direction of the spindle rod by the magnetic field.
25. The drive device according to claim 24, wherein the permanent
magnet magnetically attracts the one of the first brake element and
the second brake element, which is configured to be axially
displaceable, toward the other of the first brake element and the
second brake element.
26. The drive device according to claim 24, wherein the one of the
first brake element and the second brake element is displaceable in
the axial direction so far toward the other of the first brake
element and the second brake element that the first brake element
and the second brake element can touch each other.
27. The drive device according to claim 26, wherein the first brake
element and the second brake element are displaceable relative to
each another to such an extent that the first brake element and the
second brake element do not touch.
28. The drive device according to claim 24, wherein the one of the
first brake element and the second brake element, which is
configured to be axially displaceable, is configured to be at least
partially ferromagnetic.
29. The drive device according to claim 28, wherein the magnetic
field generated by the magnet arrangement penetrates the one of the
first brake element and the second brake element, which is
configured to be axially displaceable.
30. The drive device according to claim 24, wherein an axial
displacement of the one of the first brake element and the second
brake element, which is configured to be axially displaceable, is
controlled by the magnetic field strength generated by the magnet
arrangement.
Description
[0001] The invention relates to a drive device for a pivotable
vehicle.
BACKGROUND
[0002] Drive devices for pivotable vehicle flaps are known from
practice which are hingedly connected to a body part of the vehicle
at a first end and hingedly connected to a vehicle door at a second
end. The drive devices are generally designed as linear drives such
that, in operation, the first end of the drive device and the
second end of the drive device are linearly movable relative to
each other, as a result of which the vehicle door is pivoted in a
motor-driven manner. Thus the role of the drive device is for one
that of ensuring the vehicle door is automatically pivotable
between a closed position and an open position and further to
provide an arrest of the vehicle door in any position between the
fully closed and fully open position. Accordingly, the drive
devices for pivotable vehicle flaps should, in addition to the
drive function, also provide a braking function during the
displacement of the vehicle flap.
[0003] DE 197 52 543 A1 discloses a magnetic brake having a first
rotationally fixed brake element and a second rotatable brake
element. In a braking position of the magnetic brake, the first
brake element and the second brake element are frictionally or
positively interconnected such that the first brake element is held
or at least braked by the second brake element. The magnetic brake
therein comprises an electromagnet, which, with appropriate current
supply, displaces the first and the second brake element with
respect to each other into the braking position or a disengaged
position, wherein the braking force in the braking position has a
particular value. The magnetic brake comprises, in addition to an
electromagnet, a permanent magnet and a spring device which biases
the first brake element and the second brake element toward the
braking position. A drawback of the disclosed magnetic brake is
that the braking force cannot be flexibly adapted, but rather
substantially assumes only a particular value in the braking
position.
[0004] DE 10 2007 026 796 A1 discloses a door arrester for vehicle
doors, wherein the door arrester comprises a brake device, wherein
the brake device comprises a first brake element and a second brake
element, which brake elements each have mutually facing friction
surfaces, wherein a rotational movement of the first brake element
relative to the second brake element is decelerated by contact of
the friction surfaces. The first brake element and the second brake
element therein are made of a ferromagnetic material, wherein the
brake elements are reversibly magnetizable. The brake device
further comprises a spring element which biases the first brake
element relative to the second element toward a disengaged position
of the brake device. A drawback of the disclosed door arrestor is
that the braking force of the brake device is significantly
influenced by the spring element and also the electromagnet must be
energized in order to achieve a permanent braking action. By
providing a spring, the brake device is also susceptible to
faults.
[0005] DE 39 06 069 A1 discloses a brake device comprising a first
brake element and a second brake element, which brake elements each
have a brake pad and at least one compression spring being
associated with each brake element. The brake device has a housing
in which a current-carrying magnetic coil is received. The
compression springs associated with each of the brake elements bias
the brake elements such that the respective brake pads are in
contact with each other and thus the brake device is in a braking
position. By energizing the coil, the brake elements are displaced
relative to each other such that the brake device is brought into a
disengaged position, i.e. the brake pads of the brake elements no
longer touch. A drawback of the disclosed brake device is that
additional springs are associated with each brake element, as a
result of which the susceptibility of the brake device to faults
increases and the braking force cannot be precisely controlled.
[0006] DE 10 2015 221 067 A1 discloses a drive device for a
pivotable vehicle flap, comprising a first housing part and a
second housing part, wherein the first housing part and the second
housing part are designed to be movable relative to each other in
the direction of the axial extension of the drive device. A spindle
rod is rotatably arranged on the first housing part and a spindle
nut is non-rotatably arranged on the second housing part. A drive
device is arranged in the first housing part, wherein the drive
device comprises an electric motor. The electric motor has a
housing, wherein a first brake element, consisting of a return
element and a permanent magnet element rigidly connected to the
return element, is rigidly connected to an inner wall of the
housing. Further the electric motor comprises a drive shaft, on
which a second brake element, likewise consisting of a return
element and a permanent magnet element, is non-rotatably arranged.
An intermediate element is arranged between the permanent elements.
The permanent magnet elements are used for generating a braking
force between the brake elements and thus for a deceleration of the
drive shaft of the electric motor. A drawback of the disclosed
drive device is that the braking force is not variable and the
holding force is not flexible, as it is defined by the permanent
magnets and cannot be varied further.
SUMMARY
[0007] The present disclosure provides a drive device for a
pivotable vehicle flap, which drive device provides simple and
reliable automatic pivoting as well as a flexible holding force for
a vehicle flap.
[0008] According to one aspect of the invention, a drive device for
a pivotable vehicle flap is provided, comprising a first housing
part and a second housing part, wherein the first housing part and
the second housing part are designed to be movable relative to each
other in the direction of the axial extension of the drive device.
The drive device further comprises a spindle rod, wherein the
spindle rod is rotatably arranged on one of the first housing part
and the second housing part. The drive device further comprises a
spindle nut non-rotatably arranged on the other of the first
housing part and the second housing part, and a brake device. The
brake device comprises therein a first brake element non-rotatably
connected to the spindle rod, and a second brake element
non-rotatably connected to one of the first housing part and the
second housing part, wherein the first brake element can interact
with the second brake element to generate a braking force. Finally,
the drive device comprises a magnet arrangement for generating a
magnetic field. At least one of the first brake element and the
second brake element can be displaced by the magnetic field in the
axial direction of the spindle rod. This advantageously makes it
possible to influence the braking force caused by the brake device
in a controlled manner by controlling the magnetic field strength
of the magnetic field. Particularly advantageously, continuous
holding of the vehicle door for a wide variety of situations and
external circumstances, such as temperature, opening angle and
forces acting on the vehicle door from the outside, can be achieved
by setting the magnetic field strength.
[0009] The first housing part and the second housing part are
expediently components of a housing of the drive device, wherein
the first housing part and the second housing part are arranged
concentrically with respect to each other. The housing
advantageously makes it possible to protect movable mechanical and
electrical components of the drive device from dirt and other
external influences. In addition, it is thus avoided that a user
comes into contact with internal components of the drive device and
possibly gets injured in the process.
[0010] In a particularly preferred embodiment, the magnet
arrangement comprises an electromagnet. As a result it is
particularly advantageously achieved that the magnetic field
strength, and thus the braking force which is generated by the
brake device, can be defined by specifying the current intensity
flowing through the electromagnet. The brake device particularly
hereby preferably comprises an electric controller which can
control the current intensity or electrical power of the
electromagnet. The controller of the current intensity or
electrical power of the electromagnet is particularly preferably
programmable such that a predefined behavior of the brake device is
possible depending on the prevailing circumstances at any one time.
In this case, the current intensity or electrical power controlled
by the electric controller depends on external parameters such as
the instantaneous acceleration of the pivotable vehicle flap or the
forces acting on the pivotable vehicle flap from the outside.
[0011] The magnet arrangement preferably comprises a permanent
magnet. This advantageously makes it possible for a permanent
braking force to be provided by the brake device, without the need
for additional electrical power. The braking force can be
expediently specified by appropriate selection of the permanent
magnet or the magnetic field strength generated by the permanent
magnet. The brake device particularly preferably comprises both an
electromagnet and a permanent magnet, since a braking force is thus
generated even in the de-energized state of the electromagnet,
wherein it becomes possible to cancel the braking force as well as
increase the braking force by appropriate selection of the current
direction through the electromagnet.
[0012] The permanent magnet particularly advantageously
magnetically attracts the one of the first brake element and the
second brake element, which is designed to be axially displaceable,
toward the other of the first brake element and the second brake
element. In a further development one of the first brake element
and the second brake element can be displaced in the axial
direction of the spindle rod so far toward the other of the first
brake element and the second brake element that the first brake
element and the second brake element can touch. The first brake
element particularly preferably has a first friction surface and
the second brake element has a second friction surface. In this
case, the first friction surface and the second friction surface
are expediently facing each other and aligned substantially
perpendicularly to the axial direction of the spindle rod.
Advantageously, the braking force generated by the friction between
the free surfaces on the spindle rod can thus be set depending on
the situation by controlling the electromagnet. It is in particular
provided that the first brake element and the second brake element
can be displaced relative to each another so far that the first
brake element and the second brake element do not touch. In this
case, both the manual opening of the vehicle door and also the
motorized moving of the vehicle door is facilitated such that the
motor provided in the drive device can advantageously have smaller
dimensions.
[0013] In an expedient embodiment, the magnet arrangement is
arranged on the first brake element or the second brake element.
Particularly advantageously it is provided, that the magnet
arrangement is arranged on the second brake element, which is
non-rotatably connected to one of the first housing part and the
second housing part. Advantageously, the installation space
required for the brake device is reduced and thus the entire drive
device is designed to be more space-saving. It is expediently
provided that the magnetic field which can be generated by the
magnet arrangement penetrates the one of the first brake element
and the second brake element, which is designed to be axially
displaceable. As a result, the axial displacement of the brake
element or the braking force between the first brake element and
the second brake element is advantageously controlled by means of
the magnetic field strength.
[0014] In a further development it is particularly advantageously
provided that the one of the first brake element and the second
brake element, which is designed to be axially displaceable, is
designed to be at least partially ferromagnetic. Thereby it is
expediently achieved that the magnet arrangement exerts a force in
the axial direction on the one of the first brake element and the
second brake element, which is designed to be axially displaceable,
by means of the magnetic field generated by said magnet
arrangement. The magnetic flux of the magnet arrangement and thus
the braking force of the brake device is particularly
advantageously controllable via an electrical controller.
[0015] The drive device expediently comprises a ball bearing,
wherein the ball bearing radially surrounds a portion of the
spindle rod and rotatably supports the spindle rod. The ball
bearing is particularly preferably arranged between the spindle nut
and the brake device. By the spacing of the ball bearing from the
magnet arrangement it is advantageously prevented that the ball
bearing from influences the magnetic field of the magnet
arrangement within the brake device, or conversely the magnetic
field influences metal components of the ball bearing.
[0016] In a further development of the drive device, the housing
comprises a third housing part. In the third housing part, a drive
means for driving the spindle rod is preferably arranged. Therein a
first fastening device for hinging to one of the vehicle flap and
the vehicle body is expediently arranged on an end of the first
housing part remote from the third housing part. Furthermore it is
expediently provided that a second fastening device for hinging to
the other of the vehicle door and the vehicle body is arranged on
an end of the third housing part remote from the first housing
part. Therein one of the first fastening device and the second
fastening device is designed as a ball socket. Particularly
preferably, the other of the first fastening device and the second
fastening device is designed as a ball joint eye. The drive device
can thus be advantageously hingedly arranged between a vehicle body
and a vehicle flap to be pivoted with respect to the vehicle
body.
[0017] In a particularly preferred embodiment, the end of the third
housing part remote from the first housing part consists at least
partially of plastic. Advantageously, the overall weight of the
drive device is thus reduced. Particularly advantageously, the end
of the second fastening device facing the third housing part is
positively received in the end of the third housing part that is
remote from first housing part and consists partially of plastic.
Particularly preferably overmoulding of the end of the second
fastening device facing the third housing part is provided.
Advantageously, this results in a particularly high strength and a
good seal of the fastening device against external influences such
as moisture.
[0018] The end of the first fastening device facing the first
housing part is expediently positively received in the first
housing part at least in portions. In particular preferably it is
provided that the end of the first fastening device facing the
first housing part is pressed into an opening in the first housing
part, The first housing part is therein preferably
hollow-cylindrical and concentrically encloses the end of the first
fastening device facing the first housing part.
[0019] In a preferred embodiment, the first fastening device has a
radially circumferential first groove, wherein a portion of the
first housing part which tapers inwardly with respect to the inside
diameter projects into the groove. As a result, the first fastening
device is advantageously securely received in the first housing
part in the axial direction and secured against displacement in the
axial direction.
[0020] The first fastening device expediently has a second radially
circumferential groove, wherein a sealing ring is provided in the
second radially circumferential groove, which sealing ring seals
the first fastening device with respect to the first housing part.
Advantageously it is thus prevented, that moisture can penetrate
into the housing.
[0021] In particular preferably it is provided that the other of
the first housing part and the second housing part comprises at
least one groove extending in parallel with the axial extension of
the spindle rod. The spindle nut expediently has at least one
radial projection which projects into the at least one groove. Thus
a drive device is advantageously provided in which external torque
support of the spindle nut is not necessary.
[0022] In a further development of the drive device it is provided,
that the spindle nut can be displaced along the axial extension of
the at least one groove. As a result, by rotating the spindle rod,
which has an external thread, which in turn is in engagement with
an internal thread provided in the spindle nut, the spindle nut can
advantageously be displaced along the axial extension of the drive
device or of the spindle rod.
[0023] The at least one groove is expediently designed as a
negative form of the at least one radial projection. It
advantageously follows for one that the spindle nut is guided
exactly along the groove and also that the spindle nut is supported
relative to the housing with respect to torques transmitted through
the spindle rod.
[0024] The drive device expediently comprises a drive element,
wherein the drive element is arranged in a drive housing
concentrically with respect to the third housing part. In
particular advantageously it is provided that the drive housing is
designed as a hollow cylinder and is welded, along its outer
circumference and at least in portions, to the third housing part.
Thus it is advantageously achieved that the drive element or the
receiving drive housing is arranged particularly securely and
firmly in the third housing part. Furthermore it is advantageously
made possible, that further mounting options can be realized, such
as the laying of required electrical supply lines, in particular
for the operation of the magnet arrangement provided in the brake
device. For this purpose, a corresponding gap is provided between
the outer circumference of the drive housing and the inner
circumference of the third housing part, through which gap
electrical supply lines can be laid.
[0025] It is provided expediently that the first housing part is
translationally sealed with respect to the second housing part by
means of a sealing ring. As a result, adequate sealing against
moisture is advantageously achieved even during displacement of the
first housing part with respect to the second housing part. In an
advantageous embodiment, in order to prevent the sealing ring from
being displaced in the axial direction during displacement of the
first housing part with respect to the second housing part, the
sealing ring is secured against axial displacement by means of a
securing element. The securing element is particularly preferably
designed as a sliding bush. The sliding bush can expediently be
fastened to the second housing part by means of a latching element.
This particularly advantageously makes it possible to replace the
sealing ring in a simple manner. In a preferred embodiment, the
sealing ring is additionally secured against axial displacement by
means of at least one support ring.
BRIEF SUMMARY OF THE DRAWINGS
[0026] Further advantages, features and properties of the invention
will become apparent from the following description of a preferred
embodiment and from the dependent claims.
[0027] The invention will now be explained in more detail based on
a preferred embodiment of the invention with reference to the
accompanying drawings.
[0028] FIG. 1 shows a longitudinal section through an embodiment of
a drive device according to the invention.
[0029] FIG. 2 shows an enlarged view of a brake device of the drive
device from FIG. 1.
[0030] FIG. 3 shows a vehicle flap arranged on a vehicle body part
and having a drive device.
DETAILED DESCRIPTION
[0031] FIG. 1 is a sectional view of a preferred embodiment of a
drive device 1. The drive device 1 comprises a housing 2 which
comprises a first housing part 3, a second housing part 4 and a
third housing part 5. The first, second and third housing part 3,
4, 5 are each designed as hollow cylinders arranged substantially
concentrically with respect to one other. The first housing part 3
is made of steel, the first end 3a of the first housing part 3
remote from the second housing part 4 having an opening in which a
first fastening device 6 is received at least in portions for
hinging the drive device 1 to one of the vehicle body and the
vehicle flap.
[0032] The first fastening device 6 has a ball joint eye 6a on an
end remote from the first housing part 3, wherein the end 6b of the
first fastening device 6 remote from the ball joint eye 6a has a
first radially circumferential groove 6c and a second radially
circumferential groove 6d. The first radially circumferential
groove 6c is arranged closer to the ball joint eye 6a than the
second radially circumferential groove 6d. In the region of the
first radially circumferential groove 6c, the first housing part 3
has a tapering 3b, the tapered portion 3b of the first housing part
3 thus formed protruding into the first radially circumferential
groove 6a such that the first fastening device 6 is axially secured
to the first housing part 3 as a result. Furthermore, a sealing
ring 7 is provided in the second radially circumferential groove 6d
of the first fastening device 6, which sealing ring seals the first
fastening device 6 with respect to the first housing part 3.
[0033] The first housing part 3 has a smaller outside diameter with
respect to the second housing part 4 and is displaceably received
concentrically in the hollow-cylindrical second housing part 4 at
least in portions. In order to seal the first housing part 3 with
respect to the second housing part 4, a sealing device 8 is
provided at a first end 4a of the second housing part 4. The
sealing device 8 is secured in the axial direction of the drive
device 1 by means of a sliding bush 9. The sliding bush 9 has a
latching element 9a which is designed as a snap hook. The sealing
device 8 is arranged in the radial direction between an inner wall
4b of the second housing part 4 and an outer wall 3c of the first
housing part 3. The sealing device 8 comprises two support rings
8a, 8b, between which a sealing ring 8c is secured in the axial
direction. The sealing ring 8c is preferably designed as an X-ring.
This advantageously makes it possible for the first housing part 3
and the second housing part 4 to be displaceable relative to each
another, wherein the penetration of moisture or dirt into the
housing 2 is prevented by means of the sealing device 8.
[0034] The second housing part 4 projects with its second end 4c
remote from the first end 4a at least in portions into a first end
5a of the third housing part 5. The second end 4c of the second
housing part 4 has an annular cantilevered portion 4d which rests
against an inner step 5b of the third housing part 5. This ensures
that the second housing part 4 is secured in the axial direction
toward the first fastening device 6. A ball bearing 11 rests
against the front face of the cantilevered portion 4d facing away
from the step 5b of the third housing part 5, which ball bearing
radially encloses and thus rotatably supports a spindle rod 12
concentrically passing through the housing 2 at least in
portions.
[0035] The spindle rod 12 has an external thread 12a, wherein the
external thread 12a is in engagement with an internal thread 13a of
a spindle nut 13. The spindle nut 13 is non-rotatably arranged on a
second end 3d of the first housing part 3 such that, during a
rotational movement of the spindle rod 12, the spindle nut 13 is
displaced, together with the first housing part 3, relative to the
second housing part 4 in the axial direction. The spindle nut 13
therein has a first portion 13b projecting into the second end 3d
of the first housing part 3 such that the spindle nut 13 and the
first housing part 3 are interconnected. A second portion 13c of
the spindle nut has at least one projection 13d which projects in
the radial direction and protrudes into a groove 4e extending along
the inner wall 4b of the second housing part.
[0036] At a first end 12b, the spindle rod 12 has a guide ring 14
which is used for radially guiding the spindle rod 12 in the first
housing part 3. At a second end 12c of the spindle rod 12, the
spindle rod 12 has a plurality of notches 12d which extend in the
axial direction and are used for driving the rotational movement of
the spindle rod 12. The second end 12d of the spindle rod 12
therein is, via the notches 12d extending in the axial direction x
of the spindle rod, in rotationally fixed engagement with a gear
15, wherein the gear 15 is connected to a drive element 17 via a
coupling rod 16. The drive element 17 is received in a
hollow-cylindrical drive housing 18, wherein the outer wall 18a of
the drive housing 18 is welded at least in portions to an inner
wall 5c of the third housing part 5. A second fastening device 40
is arranged at a second end 5d of the third housing part 5. The
fastening device 40 is designed as a ball socket such that the
drive device 1 can be hinged to one of the vehicle body and the
vehicle flap.
[0037] A brake device 19 is provided in the axial direction between
the gear 15 and the ball bearing 11. The structure of the brake
device 19 and its mode of action will be explained in more detail
below with reference to FIG. 2.
[0038] FIG. 2 shows an enlarged view of a brake device of the drive
device from FIG. 1. The brake device 19 comprises a first brake
element 20 which is non-rotatably connected to the spindle rod 12
and is mounted, so as to be floating with respect to the axial
direction x, on a flange hub 21 which is pressed onto the notches
12d of the spindle rod 12 in a rotationally fixed manner. As a
result, the brake element 20 can be displaced in the axial
direction of the drive device 1, while the brake element 20 rotates
together with the flange hub 21 or the driven spindle rod 12. The
brake element 20 is designed as an annular brake disc having a
first friction surface 20a which is made of a ferromagnetic
material.
[0039] The brake device 19 further comprises a second brake element
22 which rests non-rotatably against the inner wall 5c of the third
housing part 5. Accordingly, the second brake element 22 functions
as a rotationally fixed brake stator, wherein the second brake
element 22 has a second friction surface 22a facing the first
friction surface 20a of the first brake element 20, wherein the
first friction surface 20a does not touch the second friction
surface 22a in the disengaged state of the brake device 19 shown
here. The second brake element 22 has an annular cavity 22b, in
which a magnet arrangement 23 is received.
[0040] The magnet arrangement 23 comprises an electromagnet 24 and
a permanent magnet 25, which are successively arranged in the axial
direction of the drive device 1. The permanent magnet 25 therein is
spaced further away from the first brake element 20 than the
electromagnet 24. The electromagnet 24 is powered via electrical
supply lines 26. The electrical supply lines 25 extend in a gap 27
between the outer periphery 18a of the drive housing 18 and the
inner wall 5c of the third housing part 5.
[0041] The mode of operation of the brake device 19 will be
explained below with reference to the embodiment shown in FIG.
2:
[0042] In the state shown in FIG. 2, the first brake element 20 is
displaced so far downward that the first friction surface 20a and
the second friction surface 22a do not touch. Depending on the
design, this state may be present in a de-energized state of the
electromagnet 24 when the magnetic field of the permanent magnet 25
is oriented such that the ferromagnetic brake element 20 is
repelled by the permanent magnet 25. In the present case, however,
the magnetic field of the permanent magnet 25 is preferably
oriented in such a way that the first brake element 20 is attracted
toward the second brake element 22. The shown disengaged state of
the brake device 19 is achieved therein by a magnetic flux oriented
opposite to the magnetic field generated by the permanent magnet
25, which magnetic flux is generated by the electromagnet 24. In
case that an increased braking force is necessary during pivoting
of the vehicle door, the electromagnet 24 is switched off such that
the first friction surface 20a of the first brake element 20 and
the second friction surface 22a of the second brake element 22
touch. Due to the friction forces occurring here, the rotational
movement of the spindle rod 12 non-rotatably connected to the first
brake element 20 is decelerated. If the braking forces have to be
further increased, the electromagnet 24 is powered in the reverse
orientation direction such that the magnetic flux generated by the
electromagnet 24 provides for an increased attractive force of the
first brake element 20 toward the second brake element 22.
[0043] FIG. 3 shows a vehicle flap 80 which is pivotably arranged
on a vehicle body part 70 and comprises a drive device 101. In this
case, the drive device 101 is hingedly connected to the vehicle
body part 70 with a first end 103a and to the vehicle flap 80 with
a second end 105d such that when the first end 103a is displaced
relative to the second end 105d, the vehicle flap 80 is pivoted.
For this purpose, the first end 103a of the drive device 101 is
guided through a recess 71 of the vehicle door 80.
[0044] A drive device has been disclosed above with reference to an
embodiment, in which drive device only the first brake element can
be displaced in the axial direction. It has to be understood that,
additionally or alternatively, the second brake element may be
floatingly mounted, the second brake element still remaining
rotationally fixed with respect to the housing and the first brake
element rotating together with the spindle rod.
[0045] A drive device has been disclosed above with reference to an
embodiment, in which device the housing parts, at least in part,
project one into the other and are sealed with respect to one
another. The housing parts are accordingly elongated such that the
housing composed of the housing part envelopes almost the full
length of the drive device. It has to be understood that the
housing parts may also have a compact design such that they
envelope only the spindle rod and the spindle nut. The housing
parts do not have to be sealed with respect to one other. As a
result, the dead weight of the drive device and the material costs
can be reduced.
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